Mine came with the GE JAN 5670W tube. I found it quite nice and relaxed. I then tried a Tung Sol 2C51 and it is much more precise and accurate. Not "tubey" at all. I recently bought some Russian 6N3PE (6H3NE) tubes for very cheap ($1.25 each) and they are my new fave. Wonderful detail, 3d sound, realistic. Really good.
What the Havana is sitting on is important to the sound. Try some different supports like firm and light vs cushion or inner tube. They all have different sounds.
Lastly, I also swapped out the dac chips for a better spec pair. Not expensive, but very worthwhile. This is a seriously good dac that competes well with my vinyl rig. Totally enjoyable to listen to for hours without fatigue.
What the Havana is sitting on is important to the sound. Try some different supports like firm and light vs cushion or inner tube. They all have different sounds.
Lastly, I also swapped out the dac chips for a better spec pair. Not expensive, but very worthwhile. This is a seriously good dac that competes well with my vinyl rig. Totally enjoyable to listen to for hours without fatigue.